The if and else control structures are used to execute based on a condition, where it performs the function when the condition is satisfied and performs an alternate function when the condition fails. (The else clause is not mandatory.) We can implement nested conditions as well in R.

if(<condition>) { 
## do something 
} else { 
## do something else 
}

The for loop is used to execute repetitive code statements for a definite number of iterations. The for loops are commonly used to iterate over the element of an object (list, vector, and so on).

for(i in 1:10) { 
print(i) 
}

The while loops are used to evaluate a condition repetitively. If the condition is true, then the expression in the loop body is executed until the condition becomes false.

count<-0 
while(count<10) { 
print(count) 
count<-count+1 
}

The repeat statement executes an expression in the loop repeatedly until it encounters a break.

The break statement can be used to terminate any loop. It is the only way to terminate a repeat loop.

> sum <- 1
> repeat
{
sum <- sum + 2;
print(sum);
if (sum > 11)
break;
}
3
5
7
9
11
13

The next control structure is used to skip a particular iteration in a loop based on a condition.

The return control structure signals that a function should exit a function and return a given value.

for(i in 1:5) { 
if(i<=3) { 
next 
} 
print(i) 
}
[1] 4
[1] 5